Justin Bieber's Valentine's date with 6-year-old cancer patient

Feb 15, 2012 at 9:11 a.m. ET

The "Get Avalanna to Meet Justin Bieber" campaign makes dream come true for cancer-stricken New England girl.

One of the world's biggest Beliebers just hobnobbed with her idol!

Avalanna Routh -- a 6-year-old girl battling brain cancer -- had her wish of meeting Justin Bieber granted when a social media campaign launched by the people who know her best sent the pop star to her doorstep.

Routh is such a big fan of the Biebs that she goes by the nickname "Mrs. Bieber" and was "wed" to Justin in a mock Tom Thumb Wedding. Don't tell Selena, but Avalanna was the bride at a pretend wedding to Justin last year.

Routh also holds the distinction of being the longest-standing Belieber. The brave tot told reporters that she's loved the singer for the past "80 years."

In an effort to make Avalanna's wish come true, her family and friends set up a Facebook page and Twitter account to share her story in the hopes of getting Justin's attention.

And it worked.

Avalanna's dream became reality last week, when Justin's manager Scooter Braun got word of the campaign and promised he would make the meeting happen — "sooner than you think." Scooter flew Avalanna and her family to New York for a private meeting with Justin just three days later.

In a heartwarming gesture, the Biebs met the little girl. And the two spent nearly three hours playing board games, exchanging autographs and inhaling cupcakes! Avalanna tousled J.B.'s hair, gave him a peck on the cheek and got tossed up in the air.

A tweet from Justin Bieber has the power to save lives >>

"That was one of the best things I have ever done. She was AWESOME! Feeling really inspired now!" Justin tweeted after their meeting, sharing links to a few pictures from the day.

Avalanna has an aggressive form of brain cancer called atypical teratoid rhabdoid tumor (AT/RT). The Merrimac, Massachusetts native was diagnosed with the disease when she was just eight months old. She has been undergoing radiation and chemotherapy ever since.

Routh's cancer is so rare, there are only about 30 new cases diagnosed in the U.S. each year. Currently, there is no treatment for this type of cancer.

The tot's family hopes that by bringing more attention to AT/RT, they can inspire pharmaceutical companies to invest dough into developing life-saving drugs.

In January, the famous Canadian was championed for raising awareness among his legion of fans about organ donation and giving blood. The Trillium Gift of Life Network, Ontario's central organ and tissue donation agency, saw its daily donation registrations rise to over 1,200 people after a Twitter correspondence between Bieber and a 20-year-old fan in need of a double lung transplant went viral.

Visit the Cure AT/RT website to learn more about Avalanna's condition.

6-year-old with brain cancer lives her dream of meeting Justin Bieber : MyFoxBOSTON.com

Photo credit: WENN.com